fix: Prevent hanging on self-referential dependency loops (#1557)

Author: ANGkeith

src/executor.ts

@@ -98,6 +98,7 @@ export class Executor {
                 if (j.when === "manual" && !manuals.includes(j.name)) {
                     throw new AssertionError({message: chalk`{blueBright ${j.name}} is when:manual, its needed by {blueBright ${job.name}}, and not specified in --manual`});
                 }
+                assert(job.name !== j.name, chalk`This GitLab CI configuration is invalid: The pipeline has circular dependencies: self-dependency: {blueBright ${need.job}}.`);
                 toWaitFor.push(j);
             }
         }

tests/test-cases/self-dependency/.gitlab-ci.yml

@@ -0,0 +1,6 @@
+---
+job:
+  script:
+    - echo
+  needs:
+    - job

tests/test-cases/self-dependency/integration.test.ts

@@ -0,0 +1,18 @@
+import {WriteStreamsMock} from "../../../src/write-streams.js";
+import {handler} from "../../../src/handler.js";
+import {initSpawnSpy} from "../../mocks/utils.mock.js";
+import {WhenStatics} from "../../mocks/when-statics.js";
+import {basename} from "node:path/posix";
+import {dirname} from "node:path";
+
+const name = basename(dirname(import.meta.url));
+const cwd = `tests/test-cases/${name}`;
+
+beforeAll(() => {
+    initSpawnSpy(WhenStatics.all);
+});
+
+it("should not hang the program", async () => {
+    const writeStreams = new WriteStreamsMock();
+    await expect(handler({cwd, noColor: true}, writeStreams)).rejects.toThrow("This GitLab CI configuration is invalid: The pipeline has circular dependencies: self-dependency: job.");
+});